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SK2018 PCG(H)-V/P-AECM-001
D.5.
Control Logic For 4-Pipe System
Note: 4-pipe system must always be equipped with 2 valves.
COOL MODE
a)
MTV2, AUX1 and Electrical Heater are always off.
b)
If Tr ≥ Ts + 1.8ºF (or + 7.2ºF if economy contact is activated), then cool operation is activated, MTV1 and AUX2
are turned on. Indoor fan runs at set speed.
c)
If Tr < Ts, then cool operation is terminated, MTV1 and AUX2 are turned off. Indoor fan runs at set speed.
d)
The range of Ts is 60.8 - 86ºF
e)
Indoor fan speed can be adjusted to low, medium, high and auto.
f)
When turned on, MTV1 requires 30 seconds before it is fully open.
g)
When turned off, MTV1 requires 120 seconds before it is fully closed.
h)
When the unit is turned off, the indoor fan will shut down after 5 seconds.
LOW TEMPERATURE PROTECTION OF INDOOR COIL
a)
If Ti1 ≤ 35.6ºF for 2 minutes, then MTV1 and AUX2 are turned off. If indoor fan is set for low speed, then it will
run at medium speed. If it is set at medium or high speed, then it will keep running at the same speed.
b)
If Ti1 ≥ 41ºF for 2 minutes, then MTV1 and AUX2 are turned on. Indoor fan runs at set speed.
FAN MODE
a)
Indoor fan runs at the set speed while heater, MTV1, MTV2, AUX1 and AUX2 are turned off.
b)
Indoor fan speed can be adjusted to low, medium and high.
HEAT MODE
Without Electrical Heater
a)
MTV1, AUX2 and are heater always off.
b)
If Tr ≤ Ts - 1.8ºF (or - 7.2ºF if economy contact is activated), then heat operation is activated, MTV2 and AUX1
are turned on. Indoor fan runs at the set speed.
c)
If Tr > Ts, then heat operation is terminated, MTV2 and AUX1 are turned off. Indoor fan runs at Modbus 310000
setting.
d)
The range of Ts is 60.8 - 86ºF.
e)
Indoor fan speed can be adjusted to low, medium, high and auto.
f)
When turned on, MTV2 requires 30 seconds before it is fully open.
g)
When turned off, MTV2 requires 120 seconds before it is fully closed.
With Electrical Heater as Booster
a)
MTV1 and AUX2 are always off.
b)
If Tr ≤ Ts - 1.8ºF (or - 7.2ºF if economy contact is activated), then heat operation is activated, MTV2 and AUX1
are turned on. Indoor fan runs at the set speed.
c)
If Tr > Ts, then heat operation is terminated, MTV2 and AUX1 are turned off. Indoor fan runs at Modbus 310000
setting.
d)
If Ti2 < 104ºF, then the electrical heater is turned on. If 104ºF ≤ Ti2 < 113ºF, then the electrical heater maintains
its original state. If Ti2 ≥ 113ºF, then the electrical heater is turned off.
e)
The range of Ts is 60.8 - 86ºF
f)
Indoor fan speed can be adjusted to low, medium, high and auto.
g)
When turned on, MTV2 requires 30 seconds before it is fully open.
h)
When turned off, MTV2 requires 120 seconds before it is full closed.